Conventional row crop planting implements have a plurality of boxes or hoppers for accommodating seeds, insecticides and herbicides that are deposited into the ground in laterally spaced rows. The boxes are provided with covers to enclose the seeds, insecticides and herbicides within their respective boxes. The conventional covers have a tendency to be dislodged and blow off by wind of the top of the boxes. Also, the boxes must be emptied when used with a vertical-fold row crop planter when the planter is in the folded transport position. The slide lids of the invention are securely mounted on the box which prevents them from blowing off by wind. The slide lids also eliminate the need for emptying the boxes when folding a vertical-fold planter.